1. Field of the Invention
The present invention relates to a prefix translation dispersed configuration for an exchange system, and more particularly to a prefix translation dispersed configuration and method for an exchange system having a dispersed number translation processing system.
2. Description of the Conventional Art
In an exchange system, a speed of processing communication between processors considerably affects a system performance. Thus, on a hardware side processors are intended to have a dispersed configuration considering a traffic environment or an economical situation, and on a software side it has been provided programs that simplify a call processing sequence so that unnecessary IPC (Inter Processor Communication) on the sequence is not generated.
FIG. 1 is a schematic diagram illustrating an exchange system according to locations of physical resources.
As shown therein, the exchange system consists of ASSs (Access Switching Subsystems) 10 matching users to trunk lines, an INS (Interconnection Network Subsystem) 20 connecting the ASSs 10 or the ASSs 10 to a CSS 30 and a CCS (Central Control Subsystem) 30 performing general control, application and maintenance of the exchange system.
More particularly, each ASS 10 provided with a user and trunk line matching device, a time switch and various signal devices performs dispersed call process. The ASS 10 systematically having a horizontally dispersed configuration to the INS 20 and forty four ASSs 10 at its maximum can be connected to the INS 20. The INS 20 performs number translation, that is, prefix and suffix code translation, route control, space switch connection, user information storing and management. Thus, blocks that perform call processing functions, such as number translation, routing and switching functions, are located in the INS 10. While, the CCS 30 has statistics on maintenance and application of a system, mass storage control/management, and user instruction control.
In such an exchange system, when a call is generated by a user, the ASSs 10 requests information of the user to the INS 20. The ASSs 10 which receive an originating user information perform a necessary call service function and request number translation to the INS 20 which translates the number and sets a speech path of the incoming outing ASSs through speech path search and connection. ASSs (not shown) on a call receiving side perform incoming call services. When the call is completed, the incoming outing ASSs return call data to idle states and the originating ASSs 10 inform the CSS 10 of charging data.
In addition, a failure state of the ASSs 10 or the INS 20 is informed to the CCS 30 which performs the application and maintenance of the exchange system in accordance with the received information and transmits a corresponding instruction to the ASSs 10 or the INS 20.
The number translation must be served to all calls going for destinations and a telephone number (hereinafter, called digits) which the user dials is a key to the destination, which means the originating user assigns a specific called subscriber. Accordingly, all the calls are determined whether to be received to a specific line or to be outgone to a station by the number translation.
The number translation which becomes the key to the call connection is divided into prefix translation and suffix translation and those translation performances are generally carried out in the INS 20. Thus, the exchange system stores number data therein as a table to analyze a prefix, a special service code, a suffix and an area code which can be processed in an intra-office for the number translation, and retrieves prefix and suffix tables with received digits as a key, thereby translating a corresponding number.
FIG. 2 is a block diagram which detaildely illustrates a conventional number translation processing configuration.
As shown therein, the conventional number translation processing configuration is constituted of a call control block 11, a call shared library block 12 and a trunk control block 13 that are provided in the ASS 10 and a number translation block 21, a number data processing block 22 and a route control block 23 that are provided in the INS 20. Thus, the number translation is accomplished by the IPC transmission and receive between the ASS 10 and the INS 20 and a call processing function from a call start and a call cancel is accomplished by a linkage of the call control block 11 of the ASS 10, the number translation block 21 of the INS 20, a switching block (not shown) and the route control block 23.
Specifically, the call control block 11, in accordance with characteristics of a terminal, has at least twenty blocks including a general voice subscriber call control block, a general ISDN (integrated service digital network) subscriber call control block, a packet subscriber call control block, a V5.2 subscriber call control block, an R2 call control block, a No 7 trunk call control block, and various special service call control blocks, the call control block 11 performing a required call service and collecting the predetermined number of digits from a subscriber terminal or a trunk, for thereby calling the call shared library 12. Here, the number of initially required digits which is previously set is generally 3 used for the number translation.
The call shared library block 12 extracts digits and various call informations required for the number translation from a common area in accordance with a library call from the call control block 11, the extracted digits and informations being outputted to the INS 20 through an IPC link 50. The trunk control block 13 seizes a trunk for transiting a call to the terminating station in accordance with a trunk seizing signal which is inputted from the route control block 23 through an IPC link 52.
Further, the number translation block 21 retrieves prefix and suffix tables in a point-to-point manner with digits received from the call shared library block 12 as a key and thus informs the call control block 11 of a corresponding information and a translation result through an IPC link 51 if there is a corresponding prefix or suffix. The number translation block 21 requests the route control block 23 to perform an outgoing routing process when the translation result is proven that a call type is an outgoing.
The number data processing block 22 performs generation, reference, change and cancel of data related to a prefix which is necessary for the number translation in accordance with an instruction of an operator, while the route control block 23 searches a route through which a corresponding call is transited in accordance with the outgoing routing request of the number translation block 21 and then outputs a trunk seizing control signal.
Now, an operation of the conventional number translation processing configuration will be described with the accompanying drawings.
When a call is generated from a user or an originating station, the call control block 11 collects digits, for example, three digits, that are necessary for the prefix translation through a user terminal or trunk. When the digits which are necessary for the prefix translation, the call control block 11 calls a prefix translation request library of the call shared library block 12 and thus extracts the digits and various call informations necessary for the prefix translation and requests the prefix translation to the number translation block 21.
The number translation block 21 translates the received prefix, that is, searches the prefix table of the number data processing block 22 in the point-to-point manner with the received digits as a key, thereby checking whether there exists a prefix corresponding to the received digits. As a result of the translation, if the corresponding prefix exists, that is, the received digits are a normal prefix, the number translation block 21 obtains information required for a process of an outgoing call, an incoming call, a transit call or an intra-office call from the prefix table in accordance with a call type and then informs the call control block 11 of a prefix translation result through the IPC link 51. Here, the prefix table (or a suffix table) is defined as data that can be only accessed by the INS 20.
If the call type is the outgoing call or transit call and there are sufficient digits for a routing process in the number translation block 21, the number translation block 21 requests the route control block 23 to directly perform an outgoing routing process and informs the call control block 11 of which the translation result is turned out to be an outgoing prefix. Thus, the route control block 23 searches a route through which the outgoing or transit call is transited and requests the trunk control block 13 to seize a trunk and then the trunk control block 13 seizes the corresponding trunk and transits the call to a terminating station.
While, if the digits are insufficient, the number translation block 21 obtains the number of digits necessary for the prefix translation and requests additional digits to the call control block 11. If the prefix is unobtainable or changed, the number translation block 21 informs the call control block 11 of the corresponding result. Thus, the call control block 11 requested to provide the additional digits collects additional digits as many as the number of necessary digits from the user terminal or the originating station and requests again the prefix translation to the number translation block 21.
In the conventional exchange system, data related to the number translation, such as the prefix table and the suffix table, are accessible only in the INS. Thus, the number translation process (the prefix and suffix translation) carried out with reference to the number translation related data is only processed by the INS. Accordingly, in congestion of calls, the number translation process weighs load of the INS and thus an overall call process capacity of the system becomes subject to performance of the INS, which affects the exchange system in terms of the service as well as the performance.
Also, as shown in FIG. 3, when translating the prefix, it is required to have two IPC messages between the ASS and the INS, one is for requesting the prefix translation and the other is for informing the prefix translation result), in its best situation. When the prefix translation result is the outgoing call, an IPC message is added thereto for a routing operation. However, a worse case, that is the additional digit request, is repeatedly carried out, it can be seen that the IPC message increases twice, which worsens an INS busy hour bottleneck. Further calls requesting the number translation occupy resources of the system in a waiting state, thereby lengthening delay time of a call.
Accordingly, the present invention is directed to a prefix translation dispersed configuration and method for an exchange system which obviates the problems and disadvantages in the conventional art.
An object of the present invention is to provide a prefix translation dispersed configuration and method for an exchange system that disperses a prefix translation process to ASSs from an ASS.
Another object of the present invention is to provide a prefix translation dispersed configuration and method that has a library which takes complete charge of prefix translation in each ASS and thus performs a prefix translation request generated during a call process through a library call.
Another object of the present invention is to provide a prefix translation dispersed configuration and method that simplifies a duplicated procedure of a call control block by unifying a common procedure to a library block in the call control block.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a prefix translation dispersed configuration for an exchange system which include an INS for performing number translation except for prefix translation and common functions of a call process, and ASSs horizontally and dispersedly connected to the INS and performing basic functions of the call process and the prefix translation.
Also, to achieve the objects of the present invention, in an exchange system consisting of an INS for performing common functions of a call process and suffix translation, and ASSs horizontally and dispersedly connected to the INS and performing basic functions of the call process and the prefix translation, there is provided a prefix translation method for the exchange system which includes calling a call shared library by collecting digit necessary for prefix translation from a call control block of the ASS, calling a prefix translation library by extracting various informations necessary for the prefix translation through the call shared library and then using the extracted informations as an input parameter, performing the prefix translation by searching a prefix table with digits provided as the input parameter with a key and returning a prefix translation result to the call control block as an output parameter, and performing a call process in accordance with a pattern of the output parameter returned from the prefix translation library block.